Japan will release more than 1.3 million tonnes of contaminated water from the destroyed Fukushima nuclear plant into the sea, the government said yesterday, a move China called "extremely irresponsible", while South Korea summoned Tokyo's ambassador in Seoul to protest. The first release of water will take place in about two years, giving plant operator Tokyo Electric Power time to begin filtering the water to remove harmful isotopes, build infrastructure and acquire regulatory approval. Japan has argued the water release is necessary to press ahead with the complex decommissioning of the plant after it was crippled by a 2011 earthquake and tsunami. It says similarly filtered water is routinely released from nuclear plants around the world.